The bovine pancreatic ductal explant model has been shown to be an excellent system to study pancreatic chemical carcinogenesis. Exposure of the explants to nitroso compounds such as dimethylnitrosamine, N-methyl-N-nitroso-N'-nitroguanidine and others have produced morphological alteration suggestive of adenocarcinoma. Ultrastructural studies on treated explants demonstrated such changes as the presence of large nucleoli with some evidence of microsegregation, an increase in the nucleo to cytoplasmic ratio as well as other atypical alterations. The inducibility and characteristics of aryl hydrocarbon hydroxylase have been determined in the bovine pancreatic ductal explant system. These studies have further demonstrated the value of this model system in the study of pancreatic carcinogenesis. Enzyme profiles of non-culture bovine pancreatic ductal epithelial cells have also been done. Enzymes assayed were: carbonic anhydrase, 5'-nucleotidase, HCO3-dependent ATPase and alkaline phosphatase. These assays will be done on bovine pancreatic ductal explants following treatment with chemical carcinogens. Not only has the bovine pancreatic ductal explant served as a system to study carcinogenesis in the bovine but it also serves as the model system for our studies with human pancreatic ductal explants.